Asus A7V266-E dead? What to check?

Indeed looks like a dead mobo, but isn't there a certain chip on it that I can replace? As the whole logic of waking up the board still works (connecting pins 4 and 5) and also shutting down the board still works by shortcircuiting pins 4 and 5 for about 8 secs...

Good information provided by PCBONEZ - capacitor replacement is what I see most people attempt, since they are some of the most common problems.  Here's a pinout of the 20-pin motherboard connector that you can check the voltages on: http://pinouts.ru/Power/atxpower_pinout.shtml.  You can force the power supply on by shorting pins 13 and 14 if you are testing the power supply by itself.

Yes shorting pins will kick PSU on and that's fine to test PSU output but don't leave them connected.
You want to -momentarily- short the pins.
If you leave them connected PSU protective shut downs 'may' be defeated by giving and endless start-up signal to the controller IC in the PSU. [Depends on PSU's internal design.]

>>Motherboard is partly working as when I connect it to an ATC PSU, the green LED starts burning and when I shortcut pin 4 and 5 on the connector, the fans start. No difference if I take out the processor, but the board for the rest remains dead.

This is either the PSU or the board.  I would try to replace the PSU being it would be the cheapest way to isolate the problem.  If this does not work, I would bet 100 bucks that the board is done.

But why could the PSU be bad? It powers the board in such a way that I can sort of "start" (connecting pins 4 and 5 like pressing the start button). After a start the fans start spinning (same speed, never ending). The PSU now powers also an internal SCSI tapestreamer IN ANOTHER COMPUTER (by the lack of wires). Works great, so the +5/+12/GND are ok. Or, and that's worth measuring, it should be the 3.3V line... Just measured it according to the pinout.ru URL. I see some differences.

First of all the colors don't match:
what should be gray is white
what should be blue is brown
what should be white is blue

Voltage though do match more or less:
+3.3V measures +3.37V
+5 measures +5.47V
+12 measures 10.98V
-5 measures -4.62V
-12 measures -8.98V
All voltages are very stable.

No idea if this is within boundaries, it powers an internal tapestreamer (that's only +5V or +5 and +12) perfectly... The -12V is quite low with -8.98, but I'm not sure if this is due to the load (non).

PC bonez: momentarily connecting 13 and 14 only helps for the duration of connecting, in order to measure voltages, they needed to be connected... Maybe you mix it up with the pins on the mobo, those indeed only need a very quick contact.

No capacitor problem, I can have a real close look to the mobo as it's not build in but on my desk.

By the way, this is definitely a hobby project, enough working computers, it's just that I can't stand that it's not working.

OK, unless there are other suggestions, I declare the mobo as dead... Switched PSU's withthe computer I'm no working on, although I didn't expect a solution here and no beeps, nothing. Inserted a videocard in the AGP-slot, unfortunately I don't have a PCI-videocard (as that could also be the problem, but then again, there should always be beeps), inserted some memory. Nothing happens. The other PSU seems ok.

I'll check ad BadCaps.

Would it be fair to donate the points to PCbonez, that was the most informative answer, or shall I (qually?) split the points? Plz advise...

Regards,

George

PSU and motherboard have parts in parallel that work together. (Primarily noise filters and regulators.)
If one of those parts is broken in either one the parts on the other will be overloaded and can fail too.
-
Additionally anything that causes a power spike or excess current in either mobo or PSU will be felt by the components in the other.

A power surge from the wall socket can ruin the blender.
A short in the blender will trip the main breaker.
- Kind of the same thing. - Effects of electricity go both ways.

ATX Voltage Specs Follow:
+3.3v, +/-5% - [ 3.1v-3.5v ] - okay
+5v,  +/-5% - [ 4.75v-5.25v ] - you are out high
+12v, +/-5% - [ 11.4v-12.6v ] - you are -WAY- out low
-5v, +/-10% - [ 4.5v-5.5v ] - you are out high
-12v, +/-10% - [ 10.8v-13.2v ] - you are -WAY- out low
+5vsb, +/-5% - [ 4.75v-5.25v ] - you didn't say

With the 12v out low and 5v out high your PSU has a regulation problem.
- I've only seen numbers that bad in really cheap PSU's.
- With 12v that low CPU may not even be have power because VRM won't turn on.

Bad PSU may have killed motherboard instead of the other way around.

Colors aren't the most important; the voltages are.  The negative voltages are not too important, as they are no longer used in P4 systems and later.  If you put the PSU under a load like a hard drive, you may see how it holds up when current is required.  Unfortunately, when a power supply goes, as PCBONEZ mentioned, there is a chance other parts connected to it can be knocked out as well.  You'll need to test with a good working PSU to determine if it's just the PSU that is bad.

So, with what everyone else has said, get a used but working PSU that is compatible with your ATX board.  Test it out.  It's the easiest way to determine if your board has passed on to the next life. :)  Even if you have to buy a PSU to do this, it's only going to cost 30 bucks.  IMO, that's a pretty cheap diagnosis fee, plus you'll have a working PSU regardless :)

OK, see my previous post, after measuring I switched PSU's... The one in the computer I'm now working on was used to power the faulty board. Although voltages were out of tolerances, that di not seem to be the (only) problem. The PSU I'm now working with on this computer must be 100% ok, as this computer works flawlesly...

Therefore the mobo seems dead. Not a capacitor prob. The other PSU might be gone either, but actually I don't think so. I guess when there is a normal mobo load, the voltages will be ok (didn't measure will plugged to the mobo).

I call it a day. Please have a look at my question reg. splitting the points; plz let me know.

George

You can choose as many comments as you want, if you thought they helped.  If they didn't help, don't give points to them.

-5v went away with the ISA slot except for a few odd-ball early P4 MSI boards.
-12v is still used for something I think but off the top of my head I can't remember what it is.
I'll check.

According it Intel's i845GV Chipset Design Guide it goes to those silly CNR slots if you gave one of those.